Development of monolithically integrated photonic circuits will enhance the functionality, reliability, and cost effectiveness of optical subsystems. However, the packaging of both discrete devices and optoelectronic integrated circuits (OEICs) often requires active alignment of optical fiber pigtails that substantially increases the cost of such components. Techniques for cost-effective fiber coupling of lasers, using passive rather than active alignment, have been demonstrated using separate silicon substrates that incorporated V-grooves for fiber placement.
In particular, mechanical features such as fiducials are etched into a silicon substrate platform, and serve as reference pedestals for positioning a chip which abuts against the pedestals.
Examples of prior art alignment techniques may be found in Armiento et al., "Passive Coupling of InGaAsP/InP Laser Array and Single-Mode Fibers using Silicon Waferboard," Electronic Letters, pp. 1109-1110 (1991), Cohen et al., "Passive Laser-Fiber Alignment by Index Method," IEEE Trans. Phot. Tech. Letters, Vol. 3, pp. 985-987 (1991), and U.S. Pat. No. 5,077,878.